The period of support requested in this application will be used to plan an international collaborative study describing the epidemiology of non-insulin dependent diabetes mellitus (NIDDM) in multiple populations of West African origin. Study sites will be developed among black populations in West Africa (the Republic of Cameroon), the Caribbean (Jamaica/Barbados), the United Kingdom (Manchester, England) and the United States (Chicago, IL). The investigators participating in this study bring together the resources of major research institutions in each geographic area. As a group they are actively involved in research on diabetes and cardiovascular diseases among persons of African origin, and three of the centers are currently collaborating in an NIH-supported study on hypertension in their respective populations. While NIDDM remains uncommon in West Africa, blacks in the Caribbean, the UK and the US experience high rates, and the prevalence has increased over the last two decades. The design of this study will provide cross-cultural comparisons across four stages of social development: (1) maintenance of the traditional life-style of West Africa, (2) rapid transition of the developing economy of the Caribbean, (3) acculturation of first and second generation immigrants to England, and (4) long-term assimilation into the US. Cross-sectional studies at sites representing each of these stages in the process of modernization will provide the opportunity, to the extent possible today, to reconstruct the evolution of NIDDM from a low prevalence disorder in African communities to the high rates of industrialized urban areas in the US and UK. Data currently available suggest that an interaction may exist between the level of obesity, the most important underlying risk factor for NIDDM, and the rate of modernization. The four-stage design proposed here will also make it feasible to investigate these potentially important interactions. It is further evident that these populations share a common ancestry, although direct quantitative measurements of genetic resemblance will be required. The impact of admixture and population-specific genetic factors can be studied within this framework. The ultimate aim of this study will be to provide the epidemiologic data base required to plan intervention strategies aimed at reducing the burden of NIDDM among populations of West African origin. This long-term aim can only be accomplished after the systematic acquisition of extensive survey data, and their appropriate analysis. Development of an international collaborative research group, with demonstrated access to populations and clinical support facilities, will provide a basis for designing definitive studies on the social and genetic factors which may have contributed to the epidemic of diabetes now being experienced by persons of African origin.